Field
The present disclosure generally relates to wireless communication systems and, more specifically, to improving the functionality and efficiency of power amplifiers therein.
Description of Related Art
Power amplifiers (PAs) are widely used in networks in order to set the transmission power level of an information-bearing signal. For example, PAs are used to set the pulse emission energy of lasers in optical networks. PAs are also included in various wireless network devices—such as base stations and mobile devices—in order to set the transmission power level of a radio-frequency (RF) signal. PAs are also used in local area networks in order to enable wired and wireless connectivity of various devices.
Managing PA operation is a concern in mobile devices because PA operation often characterizes the signal transmissions of a mobile device. As such, a PA is designed to satisfy performance goals driven by its intended use. Yet, design choices that satisfy some performance goals can be detrimental to others. For example, efficiency and output power are often competing performance goals. In turn, previously available PAs designs tend to prioritize one of output power and efficiency. PA designs that prioritize efficiency are often based on envelope tracking (ET), while PA designs that prioritize output power are often based on average power tracking (APT). ET includes adjusting the voltage supply of a PA in relation to the envelope of an input RF signal amplified by the PA, while APT includes adjusting the voltage supply based on the average output power of the PA. A PA designed to use ET typically has a higher load line in order to operate with higher efficiency. A PA designed to use APT typically has a lower load line in order to deliver more saturated power.
ET and APT each have advantages for respective signaling configurations. So it can be useful to enable switching between ET and APT in response to real-time signaling configuration changes. Using previously known technology, such switching involves two distinct PA modules, which is costly and increases the component count and device size. Consequently, a tradeoff is often made in which only one of an ET or APT based PA is selected. If an ET-based PA is selected, the PA will exhibit undesirable output power performance for some signaling configurations. If an APT-based PA is selected, the PA will typically exhibit undesirable efficiency performance for other signaling configurations. In both cases, the selected PA will fall short of satisfying respective performance measures for various corresponding signaling conditions.